The government imposed 10% price cuts on energy firms from January and flagged further cuts.
The cuts have alarmed power companies, who say they will have to foot the bill. However, the policy plays well with Hungarians who are struggling to pay household bills.
Orbán needs to boost his support because is seeking another term in office in an election next year.
"On behalf of the government I must say that the decision of the court is scandalous," Orbán said. He said the government would not accept the decision and would submit a new proposal to parliament for even bigger price cuts.
The prime minister said the court was expected to make a separate ruling related to electricity prices next week.
Hungary's utility sector is mostly foreign owned, with the biggest players including Germany's RWE and E.ON AG and France's GDF and EDF.
The energy price cuts were the latest in a series of unorthodox policies by the Hungarian government in the past three years that have worried investors and the International Monetary Fund.
Other steps have included Europe's biggest tax on banks and windfall taxes on energy, retail and telecommunications firms.
